The invasive American Eastern Cherry Fruitfly Rhagoletis cingulata in the Netherlands(Diptera: Tephritidae)In 2003 the European Invertebrate Survey - Netherlands, on request of the Plant ProtectionService of the Netherlands, conducted a survey of the distribution and phenology of theAmerican Eastern Cherry Fruitfly Rhagoletis cingulata (Loew, 1862). The focus of this surveywas the province of Zeeland, because the first records stemmed from this province (VanAartsen 2001). Three populations were monitored with Pherocon am yellow sticky traps(without attractant). Two of these populations were on the peninsula of Walcheren (‘Zandput’and ‘Oranjebos’, both near the town of Vrouwenpolder) and one on the island of Schouwen(‘Het Zeepe’, near the town of Burgh). This survey was supplementary to the surveys of theNational Plant Protection Service, conducted in commercially grown cherry orchards in2003-2006. In this paper an overview is given of the results of these surveys, supplementedwith a few scattered records of others.Rhagoletis cingulata is a well-known and severe pest in commercially grown cherries in NorthAmerica. This originally Nearctic species is listed as a quarantine species in the EuropeanCommunity (Annex 1a1 of the Council Directive 2000/29/ec) of which introduction into,and spread within, all member states should be banned.In the Netherlands R. cingulata should be regarded as an established species that has beenintroduced by man and which has sustained populations for more than ten years. Exterminationof this species, as required by eu legislation, is therefore useless. Meanwhile several eu memberstates have asked the European Committee to remove this species of the quarantine list. Giventhe distribution of its host Prunus serotina in the Netherlands it is to be expected that the actualdistribution of R. cingulata is much wider than presented in the distribution map (fig. 18).Moreover, it is discussed that it is probably able to shift to other hosts, so that it might evenspread over a yet larger part of the Netherlands. All given known (potential) hosts are nonindigenousspecies in the Netherlands and therefore mostly ignored by entomologists, probablycausing species like R. cingulata to be overlooked.The phenology of the population at ‘Zandput’ differs greatly from both other populations(fig. 10 versus fig. 9 & 11 ). Possible explanations are an intrinsic (genetic) difference betweenthe populations or the presence of a second species: the American Western Cherry FruitflyRhagoletis indifferens Curran, 1932. This has to be investigated further.The Pherocon am yellow sticky traps pose a good method for monitoring the phenology ofR. cingulata, provided the host plants in which they are placed are chosen carefully. A welldevelopedpopulation seems to be necessary, and the traps should be placed within the treetopand free from branches.The only host plant of R. cingulata in the Netherlands reported thus far is Prunus serotina.A single specimen was swept from Sorbus aucuparia, but it was probably coming from anadjacent P. serotina. Extensive examination of several other potential hosts yielded no proofof reproduction of R. cingulata on other hosts than P. serotina.